Setts



Nov. 2o, 1928. M9274? C. G. LINDSTROM GALENDER DOCTOR l Filed NW10, 192? @dawn-my! l Patented Nov. 2C, i928.

Magir? CARL G. LNDSTROM, OF VJORCESTER, MASSACHUSETTS, ASSIG'NOR IO RICE, BARTON & FALES, INC., 0F WORCESTER, Mt/SSAC-IUSETTS, A CORPORATION OF MASSACHU- SETTS.

CALENDER DOCTOR.

Application led November 10, 192'?. Serial No. 232,381.

fail to bear with equal pressure at both ends of the roll.

Reference is to be had to the accompanying,l drawings, in which Fig. 1 is a View of a part of a calender showing a pair of adjacent rolls in end elevation, and a doctor in transverse section constructed in accordance with this invention;

Fig. 2 is a bottom plan of the doctor showing the points of support;

Fig. 3 is a side View of one of the ing brackets for the doctor;

Fig. 4 is an end view of the saine, and

Fig. 5 is a plan thereof.

.Heretofora the doctor has been mounted on a doctor back which itself is supported on trunnions fastened to the ends of the doctor back. The doctor, .of course, is operated from one enc. rlhe result of this is that the doctor, which is fixed to the trunnions at the ends, has a. tendency to be twisted slightly, so that it may not bear with equal pressure at both ends of the roll.

In this invention a shaft rininingl the entire length of the doctor has been substituted for the trunnions. rlhe shaft 10 is located parallel with the axis of the roll and is operated from one end. A plurality of brackets 11 are mounted on this shaft and centered on it. Each of these brackets 11 is provided with flat surfaces 12, against which the doctor back 13 fcr supporting the flexible doctor 14, is adapted to rest. rlhis doet-or back is secured on the surfaces 12 by fastening,` screws or bolts 15 inthe usual way.

l prefer to use an cdd number of brackets, two of them near the opposite ends, one in the center, and, if the doctors are long, others between them. The center bracket which is shown in Figs. 3, l, and 5, is provided with a. key 16 extending into a keyway in the shaft 10. This key positively secures this bracket to the shaft at the center of the shaft and at the center of the doctor or rather its doctor support-- back. The bracket is also bound to the shaft by al screw 17.

Now the other brackets 18 are made in the same general shape as the central bracket 11, but there is no keyway and no binding screw. lhey serve simply as bearings for the shaft and supports for the same, and the twisting moment of the shaft is not transmitted through them at any point. They keep the doctor back the same distance from the shaft at all points, as they are bored out to lit the shaft and constitute a bearing therefor. As the twisting moment induced by the shaft is applied at the center of the doctor back, the flexing of the same is reduced by one half of what the flexing would be if the twisting moment was applied at the end of the doctor back in the usual manner. The doctor back isa comparatively flexible structure but by this method of mounting the difficulty is rcduced by half. Furthermore, if any flexing takes place, it will be the same practically at beth ends of the doctor. n this way it is impossible for one end to bear on the cylinder with any materially greater pressure than the other end. This affords a simple way of materially reducingone difficulty that has occurred in this industry. lt adds nothing to the expense and in fact, reduces it slightly and affords material improvement in practice.

Although I have illustrated a id describec only a single ferm of the invent-ion, l am aware of the fact that changes can be made therein by any person skilled in the art with out depart-ingl from the scope of the invention as expressed in the claims. Therefore, l do not wish to be li nited in these respects, but whatl l do claim is 1. rlfhe combination with a roll, a doctor and a doctor back therefor, of a shaft extending alongv the doctor back, a series of brackets on said shaft, each having a passage therethrough constituting a bearing` for the shaft, all of said brackets being' free on the shaft except near the center, the center bracket being positively secured to the shaft, whereby the turningl of the shaft will be transmitted to the doctor back entirely through this central bracket, and whereby the other brackets help support the angle iron and prevent its bending longitudinally or laterally, and whereby the flexing of the doctor back will be reduced by one half and the twisting moment will be transmitted to the extreme ends of the blade from the center equally in each direction.

2, In a support and operating device for a doctor, the combination with a sha-ft, of a doctor back located adjacent thereto, a series of brackets along the shaft, each secured to the doctor back and'each having a cylindrical passage therethrough fitting the shaft and constituting a bearing, all of said brackets except the center one being free on the shaft, so that they will not transmit the turning motion of the shaft to the doctor hack. the

positively secured thereto to transmit all the' turning motion to the shaft therethrough.

3. In a doctor support, the combination v with a shaft, and a doctor back for carrying the doctor, of means for applying the turning movement of the shaft to the doctor back at the center only and means for freely supporting the doctor back near its ends.

In testimony whereof I have hereunto affixed my signature.

CARL Gr. LINDSTROM. 

